Material Certificates to Request for Structural Steel Work

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For structural steel work, request mill test certificates (EN 10204 type 3.1 or equivalent) that match each heat or batch of steel used in your project, plus certificates for coatings such as hot-dip galvanizing. Check that the grade, dimensions, chemical composition and mechanical properties agree with your specification before approval.

Why material certificates matter

Material certificates link the steel delivered to your project with the grade and properties your design assumed. Without them, it is difficult to prove that the members installed are the ones you specified, which matters for engineers signing off on load paths, connections and fire or corrosion requirements.

For architectural metalwork such as railings, canopies and visible steel structures, certificates also protect the finish and tolerances you approved, since surface condition and coating thickness depend on the base material.

Mill test certificates and what they should show

The most common document is the mill test certificate, often issued to EN 10204 type 3.1, which is signed by the manufacturer's quality department independent of production. Look for the steel grade, heat or cast number, chemical analysis, yield and tensile strength, elongation and impact values where specified.

Steel grade and standard reference
Heat or batch number traceable to the delivered sections
Chemical composition and mechanical test results
Dimensions or reference to the applicable product standard

Certificates for galvanizing and coatings

If members will be hot-dip galvanized or powder coated, request the coating certificate or process record. For galvanizing, this typically states the zinc coating mass or thickness achieved and the standard followed. Coating thickness should be verified against the specification rather than assumed from the general process.

Ask for the galvanizer's certificate to be linked to the same heat or batch numbers as the steel, so coating records can be traced back to the original material.

Traceability: linking certificates to members

A certificate is only useful if you can match it to physical members. Ask that heat numbers are marked on the steel or recorded on the cutting list, and that the fabricator keeps a register linking each heat to the members produced from it.

This becomes important when a specific member is questioned on site, because traceability allows you to identify its certificate quickly without re-testing the whole job.

Checking certificates before approval

Review each certificate against your drawings and specification before production starts. Confirm the grade, sizes, quantities and standard references match exactly, and that the signing authority and date are clear. Missing values, unclear heat numbers or grades that differ from the specification should be resolved in writing.

For any calculation-critical value, the design engineer should confirm the properties shown are acceptable. Exact requirements depend on the design and applicable standards, so confirm limits with your engineer rather than relying on general figures.

Requesting documents in the project workflow

Include certificate requirements in the written specification at the start, not after fabrication. State which certificate type you need, what traceability is expected, and when documents must be delivered, typically before installation or with the delivery note.

Agreeing these points early avoids delays and makes the approval step part of a normal workflow: inquiry with photos, on-site measurement, drawing and specification, client approval, production, finishing and installation.

Frequently asked questions

What is an EN 10204 type 3.1 certificate?

It is a mill test certificate issued by the manufacturer's quality department, independent of production, confirming the material meets the ordered specification. It includes the test results for the delivered batch or heat.

Can I accept a copy of a certificate instead of the original?

A clear copy is usually acceptable for records, but confirm with your engineer or project requirements. Make sure the heat numbers and values are legible and match the material delivered.

Do I need certificates for galvanizing as well?

If coating performance is part of the specification, yes. A galvanizing certificate or process record should show the standard followed and the coating result, linked to the same batch as the steel.

What if the certificate grade differs from my drawing?

Do not approve production until the difference is resolved in writing. Either the material or the documents must be corrected, and the design engineer should confirm any substitution.

Common mistakes to avoid

Accepting generic material claims without heat-specific certificates is a common error. Failing to link certificates to members makes it hard to prove compliance later.

Our recommendation

Write certificate requirements into the specification before fabrication starts, and ask the fabricator to record heat numbers against each member. Have your engineer review the certificates before production approval.

Summary

Request heat-specific mill test certificates, coating records and traceability from the start, and check them against your drawings before approving production.

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